New approach for configuring kube-proxy in GKE / Kubernetes?

I can see that a recent pull request was merged to remove the annotations net.experimental.kubernetes.io/proxy-mode

and net.beta.kubernetes.io/proxy-mode

.

Currently, my reverse application proxies perform much better when proxymode is set to userspace

, and I would like to continue to use this setting after an upgrade.

Since the Google Container Engine hosts the Kubernetes master and I cannot access this VM directly, how do I set up a kube-proxy without using annotations? Ideally, I could change the cluster setup so that new nodes (after autoscaling) also use proxy mode userspace

.